The subject matter described herein relates, generally, to methods and systems for wind turbines, and more particularly, to methods and systems for reducing noise generation in wind turbines in an efficient manner.
At least some known wind turbines include a tower and a nacelle mounted on the tower. A rotor is rotatably mounted to the nacelle and is coupled to a generator by a shaft. A plurality of blades extends from the rotor. The blades are oriented such that wind passing over the blades turns the rotor and rotates the shaft, thereby driving the generator to generate electricity.
During operation of such known wind turbines, rotational transiting of the blades through air generates aerodynamic acoustic emissions in the form of audible noise. These acoustic emissions may produce noise with a decibel (dB) level that may approach or even exceed local regulatory levels. Accordingly, at least some methods exist for controlling noise from a wind turbine or a wind turbine installation including a plurality of wind turbines (i.e., a wind park). In particular, a wind turbine may be operated such that produced noise is below predetermined dB parameters. Such an operation of a wind turbine for reducing acoustic emissions is also known as noise reduction operation (NRO).
NRO typically implies that a wind turbine generates an electric power below the maximum possible power generation capacity of the wind turbine. Therefore, the operational state of a wind turbine under noise reduction operation is normally not directed to achieve a maximum power output but to comply with noise regulations applying to the wind turbine. However, during NRO, it is important to approach at maximum the capacity of a wind turbine for generating electric power.